Four biologists from Europe and North America met face to face for the first time on the UC Berkeley campus last month.

Although none of them is particularly famous as a scientist -- not one Nobel among them -- they know each other's names and work as well as if they had been working together for 10 years in the same laboratory. They share a painful experience.

Between 1999 and 2001, unbeknownst to the others, each made a simple but dramatic discovery that challenged the catechism of the same powerful industry -- biotechnology -- that by then had become the handmaiden of industrial agriculture and the darling of venture capitalists, who are still hoping they have invested their most recent billions in "the next big thing."

If any one of the experiments of these four scientists is proved through replication to be valid, the already troubled agricultural arm of biotech will be in truly dire straits. No one knows that better than Monsanto, Sygenta and other biotech firms that have so aggressively attacked the four discoveries in question.

When he was the principal scientific officer of the Rowett Institute in Aberdeen, Scotland, Hungarian citizen Arpad Pusztai fed transgenically modified potatoes to rodents in one of the few experiments that have ever tested the safety of genetically modified food in animals or humans. Almost immediately, the rats displayed tissue and immunological damage.

After he reported his findings, which eventually underwent peer review and were published in the United Kingdom's leading medical journal, Lancet, Pusztai's home was burglarized and his research files taken.

Soon thereafter, he was fired from his job at Rowett, and he has since suffered an orchestrated international campaign of discreditation, in which Prime Minister Tony Blair played an active role.

While Pusztai was fighting for his professional life, Cornell Professor John Losey was patiently dusting milkweed leaves with genetically modified corn pollen. When monarch butterfly larvae that ate the leaves died in significant numbers (while a control group fed nongenetically modified pollen all survived), Losey was not particularly surprised.

The new gene patched into the butterfly's genome was inserted to produce an internal pesticide, Bacillus thuringiensis (Bt), intended to attack and kill the corn borer and some particularly troublesome moth caterpillars.

What did surprise Losey was the vehement attack on his study that followed from Novartis and Monsanto, their open attempts to discredit his work and the extent to which mass media leapt to their support. Losey is still at Cornell, where his future seems secure.

Not true of Ignacio Chapela, a microbial ecologist in the plant sciences department at UC Berkeley. In 2000, Chapela discovered that pollen had drifted several miles from a field of genetically modified corn in Chiapas into the remote mountains of Oaxaca in Mexico, landing in the last reserve of biodiverse maize in the world.

If genes from the rogue pollen actually penetrated the DNA of traditional crops, they could potentially eliminate maize biodiversity forever. In his report, Chapela cautiously stated that this indeed might have happened. He expressed that sentiment in a peer-reviewed study published by Nature in November 2001.

After an aggressive public relations campaign mounted for Monsanto by the Bivings Group, a global PR firm that began with a vicious e-mail attack mounted by two "scientists" who turned out to be fictitious, Nature editors did something they had never done in their 133 years of existence. They published a cautious partial retraction of the Chapela report. Largely on the strength of that retraction, Chapela was recently denied tenure at UC Berkeley and informed that he would not be reoffered his teaching assignment in the fall.

When Tyrone Hayes, a UC Berkeley endocrinologist specializing in amphibian development, exposed young frogs in his lab to very small doses of the herbicide Atrazine, they first failed to develop normal larynxes and later displayed serious reproductive problems (males became hermaphrodites), suggesting that Atrazine might be an endocrine disrupter.

Hayes' subsequent experience differed slightly from the other panelists', but was no less troubling to academic scientists. As soon as word of Hayes' findings reached Sygenta Corp. (formerly Novartis) and its contractor, Ecorisk Inc., attempts were made to stall his research. Funding was withheld. It was a critical time, as the EPA was close to making a final ruling on Atrazine. Hermaphroditic frogs would not help Sygenta's cause.

Hayes continued the research with his own funds and found more of the same results, whereupon Sygenta offered him $2 million to continue his research "in a private setting." A committed teacher with a lab full of loyal students, Hayes declined the offer and proceeded with research that he knew had to remain in public domain.

This time he found damaging developmental effects of Atrazine at even lower levels (0.1 parts per billion). When his work appeared in the prestigious Proceedings of the National Academy of Sciences, Sygenta attacked the study and claimed that three other labs it contracted had been unable to duplicate Hayes' results.

Hayes, who keeps his head down on the Berkeley campus, has obtained tenure and continues to teach. But his studies that could affect approval of the most widely used chemical in U.S. agriculture are being stifled at every turn.

In a public conversation attended by 500 people and Webcast to 4,000 more worldwide recently on the Berkeley campus, Pusztai, Losey, Hayes and Chapela shared their experiences and together explored ways to prevent similar fates from ever happening to their peers. Their similar stories provide a unique window into a disturbing trend in modern science.

None of the four complained that his science had been challenged, although in each case it had. All science is and should be challenged. No one knows that better than a practicing scientist, who also knows that if tenure depended on a perfect experimental record, there would be very few tenured scientists anywhere in the world.

These four men were not attacked because of flawed or imperfect experiments but because the findings of their work have a potential economic effect. The sad part is that the academies and other allegedly independent institutions that once defended scientific freedom and protected employees like Hayes, Chapela, Losey and Pusztai are abandoning them to the wolves of commerce, the brands of which are being engraved over the entrances to a disturbing number of university labs.